The continuation of this program will include: (a) the development of neuroendocrine regulation of the pituitary-adrenal system in fetuses and neonates. In particular, these studies will concentrate on an examination of levels of circulating ACTH under basal and stress conditions. ACTH will be examined, using the newly developed cytochemical assay which has the sensitivity needed to measure ACTH in small concentrations of plasma. (b) An extensive series of investigations is planned to elaborate the finding on differential maternal responsiveness of normal and malnourished mother to shocked vs. handled pups. These studies will include not only an examination of the mother but also an examination of the stimulus properties of the offspring (ultrasound, odor, temperature change, etc.) that may be responsible for inducing elevations in maternal corticoids. (c) Problems related to the development of coping mechanisms and its converse, learned helplessness, will also be examined during the course of this research program. Questions concerning the development of coping and the relationship between early environments and coping responses will be emphasized. (d) We will continue our studies on the pituitary-adrenal system of adult and neonatal squirrel monkeys. We further plan to examine the pituitary-adrenal response of mother and infant monkeys to separation. The response of the pituitary-adrenal system to stress in the lactating female is of particular interest since we have demonstrated in the rat that lactation markedly reduces the stress response. It is hoped that the cytochemical assay can be validated for the squirrel monkey so that we can examine both ACTH and circulating corticoids in the different studies on this subhuman primate. Finally, we expect that during the period of this forthcoming grant our colony of squirrel monkeys will produce sufficient infants to make it possible to examine in detail the development of the pituitary-adrenal system.